A lot of the patterns covered in the articles below come up often in code reviews or when designing new features. There are also a couple of general dev tips & tricks articles sprinkled in there too.
Gourmet Service Objects http://brewhouse.io/blog/2014/04/30/gourmet-service-objects.html
Facade rules for controllers from Thoughtbot https://robots.thoughtbot.com/sandi-metz-rules-for-developers
Safe Operations For High Volume PostgreSQL